The D minor (Op. 31, No. 2) and the F minor (Op. 57) sonatas, not to speak of others, form the apotheosis of the sonata in three movements as established, though not invented, by Emanuel Bach.  To say that Beethoven was the perfecter of the sonata is true, but it is scarcely the whole truth.  The E minor appears a first great step in the process of dissolution; the C minor, a second.  They were great steps, because they were those of a very great man.  The experiments as to number of movements of which we spoke in our introductory chapter were interesting; and with regard to the number, and also the position of the Minuet before or after the slow movement, those experiments acquired additional interest, inasmuch as Beethoven seems for a time to have been affected by them.  The two works named are, however, of the highest importance; in them, if we are not mistaken, are to be found the first signs of the disappearance, as it were, of the sonata of three movements, and, perhaps, of the sonata itself, into the “imperceptible.”  After Op. 90 Beethoven wrote sonatas in four movements, but that does not affect the argument, neither does the fact, that after Beethoven are to be found several remarkable sonatas with the same number.  The process of evolution of the sonata was gradual; so also will be that of its dissolution.  The title of “sonata” given by Beethoven to his Op. 90 and Op. 111 does not affect the music one jot; under any other name it would sound as well.  You might call the “Choral Symphony” a Divertimento, and the title would be considered inappropriate; or a Polonaise, and the name would be scouted as ridiculous; but the music would still remain great and glorious.  Yet taking into consideration the meaning of the term “sonata” as understood by Emanuel Bach, Haydn, and Beethoven himself, it can scarcely be the right one for these tone-poems in two sections.  The sonata-form of the first movement in each case may have suggested the title.  The two early sonatas Op. 27 (Nos. 1 and 2) are both styled sonata, but with the addition quasi una fantasia.  And in neither case was the first movement in sonata-form; the one in E flat does not even contain such a movement.  There are other signs of the process of disintegration in the later sonatas.  Op. 109, in E, is peculiar as regards the form of the movements of which it is composed; and the fugues of Op. 101, 106, and 109—­a return, by the way, to the past—­show at least an unsettled state of mind.  The sonata in A flat (Op. 110) was probably the germ whence sprang the sonata in B minor of Liszt—­a work of which we shall soon have to speak.